/*const reg = /^(a|b)*?$/
console.log(reg.test('')); //true*/

/*
\s 元字符用于查找空白字符。

空白字符可以是：

空格符 (space character)
制表符 (tab character)
回车符 (carriage return character)
换行符 (new line character)
垂直换行符 (vertical tab character)
换页符 (form feed character)
*/
const reg = /\s\)/
console.log(reg.test(`
          )
`)); //false


/\$theme-default(?:(?:\s)*?)\(/.test(`$theme-default`)
